Saw tooth



Aug. 1937- R. N. s. M ERRITT 2,088,998

SAW TOOTH Filed March 13, 1936 RALPH N. 5. MERR/ i' 8; chanical featuresof this invention,

Patented Aug. 3, 1937 UNITED. STATES PATENT OFFICE SAW TOOTH Ralph N. S.Merritt, Worcester. Mass., assignor to Norton Company, Worcester, Mass.,a cornotation of Massachusetts Application March 1a, 1936, Serial No.68,598 5 Claims. (01. 125-22) The invention relates to saw teeth, andwith re gard to its more specific features to an abrasive saw toothadapted to be detachably mounted and secured in a saw blade of eitherthe circular or 6 reciprocable type for cutting stone and other hardmaterial.

One object of the invention isto provide a saw tooth of the characterindicated of durable rigid construction which shall not abrade thesocket m in which it is held. Another object of the invention is toprovide an improved method for the manufacture of a satisfactory sawtooth. An-

otherobject of the invention is to form a saw Other objects will beinpart obvious or in part pointed out hereinafter.

as The invention accordingly consists in the features of construction,combinations of elements, arrangements of parts, and in the severalsteps and relation and order of each of said steps to one or. more ofthe others thereof, all as will be 80 illustratively described herein,and the scope of the application of which will be indicated in thfollowingclaims.

In the accompanying drawing in which is shown one of many possibleembodiments of the me- Figure 1 is a side elevation of an abrasivetooth, Figure 2 is a sectional elevation taken on the line 2--2 ofFigure 1. V

Figure 3 is a side elevation of amodifled abra- 10 sive tooth.

Figure 4 is a sectional elevation taken on the line 4-4 of Figure 3.

Figure 5 is -a fragmentary view of a saw and tooth receiving socketshowing the abrasive tooth of Figures 1 and 2 held therein.

Referring now to Figures 1 and 2, the saw tooth Referring now to Figure5, the trapezoidal root i2 is mounted in a saw ll, usually made ofsteel,

in a socket l8 thereof, which socket has a front V-shaped groove l9 anda back V-shaped groove 20 the apexes of whose dihedral angles areinclin'ed to each other by the same angle as the angle between the front14 and back l5 of the' trapezoid. The socket l8 further provides aconvex V portion 2| opposite the bottom l3; A wedge 22 has V grooves inits opposite sides fitting the convex V portion 2i and the convex V 1trapezoidal portion is first passed by the opposite V portions l9 and 20until it will enter the socket It, then the tooth I0 is placed in theplane of the saw l1 and moved radially or outwardly until the front l4and the back I5 enter into wedging engagement with the V grooves l9 and20. The wedge 22 may now be inserted from the large open space 23 at oneend of the socket, and the wedge may be driven home with a lead hammeror in any other manner. The saw moves in the direction 'of the arrows,Figures 1 and 5, and consequently on starting up the inertia of thewedges 22 tends toiforce them into wedging engagement so as to lock theparts together. Nevertheless a saw tooth can be readily removed fromthesaw. I Considering now the manufacture of the tooth just described, Iprovide a quantity of abrasive grain Within the limits of this inventionany type of abrasive may be used, for example aluminum oxide in allitsflforms, or silicon carbide, diamonds, garnet, silica, or any otherdesired. abrasive material. I further. provideany suitable bondingmaterial. While various types of bonds might be used in carrying out myinvention, :I prefer to use one of the organic bonds, for examplerubber, shellac. or an artificial resinoid. In the preferred form of theinvention I use a. bond comprising a phenol-formaldehyde resin or aglycerine phthalic anhydride. resin commonly known under the name of"GIy-ptoI.

For the manufacture of theabrasive portion I] I use any of the abovenamed abrasive materials or any other suitable abrasive material. Iprefer to use silicon carbide which has excellent cutting propertieswith respect to stone. I prefer to use relatively coarse abrasive grain,for example of the order of 12 mesh size, although finer or coarsergrain may be employed. If I use an. artificial resinoid bond I prepare amixture of the abrasive grain and bond in a now known manner. The bondis rendered somewhat plastic and 'each grain is coated with a desiredamount of bond for the manufacture of the abrasive portions II of anumber of abrasive teeth l0.

For the manufacture of the root portion l2 5 I use the same bond as isused for the portion I l I use abrasive grain, the same abrasive grainas is used for the portion H, in the root portion II, but a very muchsmaller sizethereof. For example I may use grain of 60 mesh size orsmaller. Under conditions which do not involve relative speed such asare met with in grinding by grinding wheels, a fine mesh abrasive grainin an organic bond has relatively little abrasive characteristics ,onthe socket and wedge of a steel saw l1.

Taking a quantity of the fine abrasive material selected as abovedescribed, I coat it with bond in the same manner and to the same extentas the abrasive grain is coated, I prepare a separate batch thereof.Furthermore the proportion by volume of abrasive grain to bond in theportion I I should be the same as the proportion of fine grain to bondin the root portion l2, in the preferred form of my invention.

I now provide any suitable mold to form an abrasive tooth as shown.Known molds for the manufacture of abrasive saw teeth may be used.Having calculated the quantity of abrasive grain and bond by weight forthe portion II, and having calculated the quantity of fine grain andbond by weight for the portion l2 to give the same structure for eachportion from the standpoint of volume relationship of abrasive or finegrain on the one hand, bond on the other hand and pore space also, Iplace in that portion of the mold which is to form the abrasive portionII the required amount of abrasive and bond mixture. I place in thatportion of the mold which is to form the root portion I2 40 the requiredquantity of fine grain and bond mixture. The two mixtures will cometogether along the line I6. Filling the mold may be done by hand withthe aid of a trowel or a knife or the like.

45 I now press the combined mixture with the desired amount of pressure,and then cure in a curing oven in the usual manner for the type of bondused, curing -and vulcanizing being well known. The result is anintegral structure and 50 although there is a dividing, line l6separating the two portions thereof this is not a line of weakness. i

Referring now to Figures 3 and 4, the abrasive tooth thereof is madeexactly as described 55 in the case of the abrasive tooth of Figures 1and Z'excepting that the abrasive portion Ila extends further down andis bounded from the fine grain portion |2a by an irregular line I60.

as shown. In other words, the portion of fine 60 grain material In is inthe nature of a sheath around the abrasive portion Hm. From one point ofview the root of the tooth lfla consists as in the root portion 12 or12a finely divided comminuted material is used, crumbling of the edgesis avoided. By using fine grains for the 75 root portion I2 of the sameabrasive material bond. I prepare a quantity of abrasive grain and as isused for the abrasive portion II, the granular material in both sectionsis of the same specific gravity. This permits the tooth to bemanufactured in a single mold and at a single molding operation,something which is diificult when granular materials of differentspecific gravities are used. Thus the present invention presents certainadvantages in manufacture and achieves an integral product, and theseadvantages may in certain cases offset the slight abrasive qualities ofthe fine grained root portion.

It will thus be seen that there has been provided by this invention amethod and an apparatus in which the various objects hereinbefore setforth are successfully achieved. As many possible embodiments may bemade of the mechanical features of this invention, and as the art hereindescribed may be varied, in various parts, all without departing fromthe scope of the invention, it is to be understood that all matterhereinbefore set forth or shown in the accompanying drawing is to beinterpreted as illustrative and not in a limiting sense.

I claim:

1. A saw tooth adapted to be removably mounted and wedgingly clamped ina. socket of a saw blade comprising a molded body having an abrasiveportion formed of relatively "coarse abrasive grains united togetherintegrally by a bond and adapted to be exposed outside the saw socket,and a molded root formed of fine grains substantially one fifth the sizeof the coarse abrasive grains aforesaid or smaller and of the sameabrasive material as the abrasive grains aforesaid and of the same bondas forms the abrasive portion said root being integral with the abrasiveportion and shaped to be mounted in the same socket, said root having aplurality of holding surfaces shaped directly to engage and flt therespective tooth holding portions of the same socket and the clampingwedge employed therein.

2. A saw tooth adapted to be removably mount ed and wedgingly clamped ina socket of a saw blade comprising a molded body provided with anabrasive portion formed of relatively coarse abrasive grains unitedtogether integrally by an organic bond and adapted to be exposed outsideof the saw socket, and a root integral with the abrasive portion andshaped to be mounted in the saw socket, said root being formed of thesame organic bond combined with abrasive grains of the same substance asthe aforesaid abrasive grains but of very much smaller grain size, notlarger than one fifth thereof.

3. A saw tooth adapted to be removably mounted and wedgingly clamped ina socket of a saw blade comprising a molded body having an abrasiveportion formed of relatively coarse abrasive grains united togetherintegrally by an organic bond and adapted to be exposed outside of thesaw socket for a cutting operation, and a root integral with theabrasive portion and shaped to be mounted in the saw socket, said rootbeing composed of finely divided, i. e. 60 mesh size or smaller,abrasive material of the same substance as the aforesaid abrasive grainsunited together into an integral mass by the same organic bond asaforesaid.

4. A saw tooth adapted to be removably mounted and wedgingly clamped ina socket of a saw blade comprising a molded body having an abrasiveportion formed of abrasive grains united together integrally by anorganic bond and 2,688,998 adapted to be exposed ontside of the sawsocket and a root integral with the abrasive portiomand shaped to bemounted in thesaw socket; said root being composed of finely .divided'abrasive material of the same substance as the aforesaid abrasive grainsbut only a small fraction of the size thereof bonded together in anintegral mass by the same organic bond. l

5. In a stone saw having a plnrality of saw teeth adapted to beremovably mounted and wedgingly clamped in a series of sockets in thesaw blade, the combination of saw blade having a socket in the edgethereof, a; clamp wedged therein, and a replaceable cutting toothsecured body having an abrasive portion of organic bonded abrasivegrainprojecting beyond the edge of the saw blade for a cutting operationand. provided with a root of the same molded organic material integrallyunited with the abrasive portion and adapted directly to engage and fitthe wheels of the socket and the clamping wedge therein, the root havingtherein fine sized abrasive grains of a size but a small fraction of theabrasive grains aforesaid, whereby the tooth is rigidly held in placewithout detrimental

